committed by
ThomasV
8 changed files with 396 additions and 55 deletions
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# -*- coding: utf-8 -*- |
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# |
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# Electrum - lightweight Bitcoin client |
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# Copyright (C) 2018 The Electrum developers |
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# |
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# Permission is hereby granted, free of charge, to any person |
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# obtaining a copy of this software and associated documentation files |
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# (the "Software"), to deal in the Software without restriction, |
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# including without limitation the rights to use, copy, modify, merge, |
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# publish, distribute, sublicense, and/or sell copies of the Software, |
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# and to permit persons to whom the Software is furnished to do so, |
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# subject to the following conditions: |
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# |
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# The above copyright notice and this permission notice shall be |
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# included in all copies or substantial portions of the Software. |
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# |
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
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# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
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# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
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# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS |
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# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN |
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# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN |
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# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
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# SOFTWARE. |
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import threading |
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from . import lnbase |
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from . import bitcoin |
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from . import ecc |
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from .util import ThreadJob, bh2u, bfh |
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from .lnutil import invert_short_channel_id, funding_output_script_from_keys |
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from .verifier import verify_tx_is_in_block, MerkleVerificationFailure |
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from .transaction import Transaction |
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class LNChanAnnVerifier(ThreadJob): |
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""" Verify channel announcements for the Channel DB """ |
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def __init__(self, network, channel_db): |
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self.network = network |
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self.channel_db = channel_db |
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self.lock = threading.Lock() |
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# items only removed when whole verification succeeds for them. |
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# fixme: if it fails, it will never succeed |
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self.started_verifying_channel = set() # short_channel_id |
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self.unverified_channel_info = {} # short_channel_id -> channel_info |
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def add_new_channel_info(self, channel_info): |
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short_channel_id = channel_info.channel_id |
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if short_channel_id in self.unverified_channel_info: |
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return |
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if not verify_sigs_for_channel_announcement(channel_info.msg_payload): |
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return |
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with self.lock: |
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self.unverified_channel_info[short_channel_id] = channel_info |
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def get_pending_channel_info(self, short_channel_id): |
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return self.unverified_channel_info.get(short_channel_id, None) |
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def run(self): |
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interface = self.network.interface |
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if not interface: |
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return |
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blockchain = interface.blockchain |
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if not blockchain: |
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return |
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with self.lock: |
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unverified_channel_info = list(self.unverified_channel_info) |
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for short_channel_id in unverified_channel_info: |
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if short_channel_id in self.started_verifying_channel: |
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continue |
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block_height, tx_pos, output_idx = invert_short_channel_id(short_channel_id) |
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# only resolve short_channel_id if headers are available. |
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header = blockchain.read_header(block_height) |
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if header is None: |
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index = block_height // 2016 |
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if index < len(blockchain.checkpoints): |
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self.network.request_chunk(interface, index) |
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continue |
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callback = lambda resp, short_channel_id=short_channel_id: self.on_txid_and_merkle(resp, short_channel_id) |
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self.network.get_txid_from_txpos(block_height, tx_pos, True, |
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callback=callback) |
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#self.print_error('requested short_channel_id', bh2u(short_channel_id)) |
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with self.lock: |
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self.started_verifying_channel.add(short_channel_id) |
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def on_txid_and_merkle(self, response, short_channel_id): |
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if response.get('error'): |
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self.print_error('received an error:', response) |
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return |
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result = response['result'] |
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tx_hash = result['tx_hash'] |
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merkle_branch = result['merkle'] |
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block_height, tx_pos, output_idx = invert_short_channel_id(short_channel_id) |
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header = self.network.blockchain().read_header(block_height) |
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try: |
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verify_tx_is_in_block(tx_hash, merkle_branch, tx_pos, header, block_height) |
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except MerkleVerificationFailure as e: |
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self.print_error(str(e)) |
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return |
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callback = lambda resp, short_channel_id=short_channel_id: self.on_tx_response(resp, short_channel_id) |
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self.network.get_transaction(tx_hash, callback=callback) |
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def on_tx_response(self, response, short_channel_id): |
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if response.get('error'): |
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self.print_error('received an error:', response) |
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return |
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params = response['params'] |
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result = response['result'] |
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tx_hash = params[0] |
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tx = Transaction(result) |
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try: |
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tx.deserialize() |
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except Exception: |
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self.print_msg("cannot deserialize transaction, skipping", tx_hash) |
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return |
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if tx_hash != tx.txid(): |
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self.print_error("received tx does not match expected txid ({} != {})" |
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.format(tx_hash, tx.txid())) |
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return |
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# check funding output |
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channel_info = self.unverified_channel_info[short_channel_id] |
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chan_ann = channel_info.msg_payload |
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redeem_script = funding_output_script_from_keys(chan_ann['bitcoin_key_1'], chan_ann['bitcoin_key_2']) |
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expected_address = bitcoin.redeem_script_to_address('p2wsh', redeem_script) |
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output_idx = invert_short_channel_id(short_channel_id)[2] |
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try: |
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actual_output = tx.outputs()[output_idx] |
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except IndexError: |
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return |
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if expected_address != actual_output[1]: |
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return |
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# put channel into channel DB |
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channel_info.set_capacity(actual_output[2]) |
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self.channel_db.add_verified_channel_info(short_channel_id, channel_info) |
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# remove channel from unverified |
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with self.lock: |
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self.unverified_channel_info.pop(short_channel_id, None) |
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try: self.started_verifying_channel.remove(short_channel_id) |
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except KeyError: pass |
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def verify_sigs_for_channel_announcement(chan_ann: dict) -> bool: |
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msg_bytes = lnbase.gen_msg('channel_announcement', **chan_ann) |
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pre_hash = msg_bytes[2+256:] |
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h = bitcoin.Hash(pre_hash) |
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pubkeys = [chan_ann['node_id_1'], chan_ann['node_id_2'], chan_ann['bitcoin_key_1'], chan_ann['bitcoin_key_2']] |
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sigs = [chan_ann['node_signature_1'], chan_ann['node_signature_2'], chan_ann['bitcoin_signature_1'], chan_ann['bitcoin_signature_2']] |
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for pubkey, sig in zip(pubkeys, sigs): |
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if not ecc.verify_signature(pubkey, sig, h): |
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return False |
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return True |
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def verify_sig_for_channel_update(chan_upd: dict, node_id: bytes) -> bool: |
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msg_bytes = lnbase.gen_msg('channel_update', **chan_upd) |
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pre_hash = msg_bytes[2+64:] |
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h = bitcoin.Hash(pre_hash) |
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sig = chan_upd['signature'] |
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if not ecc.verify_signature(node_id, sig, h): |
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return False |
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return True |
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